Hydraulic pumps



Feb. 19, 1963 R. s. DICKINSON ETAL 3,077,837

HYDRAULIC PUMPS Filed March 16, 1960 3 Sheets-Sheet 1 RJWALD D 1 L|Lnv$om AAA INVENTORS MERVIV BALTkA/n WJ BM,WAL ATTORNEYS Feb. 19, 1963 R. s. DICKINSON ETAL 3,077,337

HYDRAULIC PUMPS Filed March 16, 1960 3 Sheets-Sheet 2 kvruALp ID/v57; DICK/A4504 1H4 INVENTORJ mEn y/v dnn'nz n 2 3 z 1 6 ATTORNEY;

Feb. 19, 1963 Filed March 16, 1960 R. s. DICKINSON ETAL 3,077,837

HYDRAULIC PUMPS 5 Sheets-Sheet 3 R n ALB JIDNE) Olen/#50 n INVENTORJ' mEm'j/ AAAT -AM tinned dtates 3,577,337 HYDRAULIC PUML S Ronald Sidney Dickinson and Mervyn Bartram, York, England, assigncrs to Armstrong Patents Co. Limited, Beverley, England, a British company Filed hiar. l6, 196d, Ser. No. 15,429 2 Claims. ((Zl. 133-41) This invention concerns hydraulic pumps, and relates more particularly to hydraulic pumps for incorporation in spring suspension systems, for example for road vehicles, wherein one region of asuspension spring is carried by a hydraulic ram to which a hydraulic medium may be supplied under pressure or from which hydraulic medium may be exhausted for the purpose of modifying the spring attitude relative to and on variation of a load supported by said spring.

According to the present invention, a hydraulic pump comprises a pump body formed with a reservoir for hydraulic medium and with at least one bore communicating with said reservoir, a semi-rotary spindle journalled in said body and adapted for reciprocation from externally of said body, a cam carried on said spindle, a plunger displaceably received in said bore and resiliently urged towards said cam for reciprocation thereby, an inlet valve for hydraulic medium at the reservoir end of said bore, an outlet valve for said medium at the opposite end of said bore, said plunger being formed with passage means to permit the flow of hydraulic medium therethrough, and a delivery conduit extending from said opposite end of said bore to an outlet connection provided on the pump body.

The outlet connection may thus be placed in communication with a hydraulic operating member such as a hydraulic ram in order, during operation of the pump, to supply hydraulic medium under pressure to said operating member. Preferably the pump is further provided with a hydraulic pressure relief valve arranged in a passage formed in the pump body to extend between the outlet connection and the reservoir, said relief valve being adapted for opening on the attainment of a predetermined angular position of said spindle within said body. For example, the passage containing the relief valve may be a further bore in the pump body, and the relief valve may have a valve member adapted for unseating by means of a plunger in said bore and having a portion extending from said bore towards a further cam fixed on the spindle, the cam being so arranged as to bear on the plunger when said predetermined angular position is reached.

For the purpose of guarding against hydraulic locks between the pump and a hydraulic operating member to which it is connected, the pump may be provided with an overload valve arranged to communicate with the outlet connection and with the reservoir, and set to open when a given hydraulic pressure is exceeded.

In a modification of the invention, instead of or in addition to forming the pump body with an integral reservoir, said body is provided with an inlet connection adapted for communication with an independent reservoir, and both said relief valve and said overload valve (when provided) are arranged to communicate with said inlet connnection and thence with said independent reseryou.

The invention will be described further, by Way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a transverse, vertical sectional elevation through one hydraulic pump embodying the invention,

FIG. 2 is a sectional elevation taken, on the line 11-11 of FIG. 1, i

3,977,837 Patented Feb. 19, 1963 ire FIG. 3 is a detail in section taken on the line III--III of FIG. 2,

FIG. 4 is a vertical sectional elevation of another embodiment of the invention, taken on the line IV-IV of FIG. 5,

FIG. 5 is a transverse vertical sectional elevation taken on the line V-V of FIG. 4, and

FIG. 6 is a sectional detail taken on the line Vl--VI of FIG. 5.

Throughout the various figures of the drawings, like reference numerals are employed wherever possible to denote like parts.

In the hydraulic pump shown in FIGS. 1 to 3, a pump body 10 is formed with an integral reservoir 12 for a hydraulic medium, and a semi-rotary spindle 14, adapted for reciprocation from externally of the body 10 by connection of a lever arm 16, for example to a vehicle suspension spring (not shown), passes through the reservoir 12 and is journalled in the body 10.

The pump body 10 is provided with a pair of bores 18, 20, and within the bore 13 is threadedly engaged a cylindrical liner 22 having displaceably received therein, a pump plunger 24 which at its upper end extends from the liner 22 towards the spindle 14. The spindle 14 has a cam 26 fixedly secured thereon, and the shape and angular setting of the cam 26 on said spindleare such that, over a wide range of angular position of the spindle, the cam bears on the plunger 24 so that angular reciprocation of the spindle results in reciprocation of the plunger within the liner 22, the plunger being resiliently urged towards cam 26 by means of a spring 23. The plunger 24 is formed with passage means 30 by which it communicates with the reservoir 12, and at its inner end, within the liner 22, is provided with a shoulder to receive a valve seat 32 against which aball valve member 34 is urged by means of a spring 36. Beyond the valve seat 32, the passage means 30 is enlarged to form a chamber 38, and thus, on upward, i.e. induction, strokes of the plunger 24, hydraulic medium is drawn from the reservoir 12, past the ball valve member 34, and into the chamber 38. At the end of the liner 22 remote from that at which the plunger 24 is introduced, there is threadedly engaged a member 40 which is bored to communicate with chamber 38 and counterbored to present a shoulder receiving a valve seat 42 whereon resiliently abuts a delivery ball valve member 44. The ball valve member 44 is housed within an end cap 46 closing the member 40 except for apertures 48 through which hydraulic medium is delivered, on downward strokes of the plunger 24, from the chamber 38 to the bore 18 of pump body 10. From the bore 13, the hydraulic medium delivered thereto passes through a conduit 50 formed in body 10 to an outlet connection 52 provided thereon and adapted for connection to a hydraulic operating member such as aram.

A typical application of the pump described above is to a vehicle spring suspension system wherein one region of the suspension spring is carried by a hydraulic ram supplied with hydraulic medium under pressure by the pump. In such a suspension system, when the load carried by the vehicle is increased and the chassis consequently sinks relative to the spring, the supply of hydraulic medium to the ram, and consequent extension of said ram, enables the chassis to be restored to its original height to compensate for the increased load. In order to allow the reverse action to occur when the vehicle loading is decreased, the pump shown in FIGS. 1 to 3 incorporates a relief valve enabling hydraulic medium to exhaust from the ram back to the reservoir 12. For this pumpose, the bore 20 of the pump body 10 is provided wtih a liner 54 which is bored at one end to present-a shoulder receiving a valve seat 56. A'ball valve member 58 is resiliently urged against the seat 56 by means of a spring 60 contained within an end cap 62 threadedly engaged within the liner 54. The upper end of the liner 54 is bored to slidingly house a plunger 64 which, at its end within the liner 54, is of reduced dimensions such as to pass through the valve seat 56 and contact the ball valve member 58. The opposite end of plunger 64 extends out of the liner 54 towards the spindle 14, and the latter is provided with a profile cam 66 against which the plunger 64 is urged by means of a spring 63. A surface 67 is provided on the cam 66 for the purpose of depressing the plunger and unseating the ball valve member 58, and the range of angular positions of the spindle 14 over which this will occur Will depend upon the initial setting of the cam on the spindle. Thus the spindle 14, via the lever arm 16 and its connection to, e.g. a vehicle suspension spring, is adapted to sense a predetermined condition of the suspension spring at which the relief valve is to be opened or closed. When the relief valve opens, hydraulic medium passes from the outlet connection 52, to the bore 20, past the valve member 58, through passage means 70 formed in the plunger 64, and back into the reservoir 12.

To guard against hydraulic locks occurring when the hydraulic ram or other operating member to which the pump is connected is fully extended, the pump further includes a passage 72 formed in the body between the conduit 50 and the reservoir 12, and an overload valve arranged in said passage and having a valve member 74 urged resiliently against a seat 75 by means of a spring 78. The spring is retained in position by means of a threaded nut 80, and hence the nut 80 may be adjusted to set the spring and hence valve member 74 to open at a desired maximum pressure.

It will be appreciated that, in the embodiment of FIGS. 1 to 3, there may be more than one cam and plunger assembly 2248 provided, by suitably shaping the body 10 to have more than one bore 18, and by providing a corresponding number of earns 26 on the spindle 14.

In contrast to the pump described above, wherein the bores 18, and their respective plunger and relief valve assemblies are arranged beneath and in line with the spindle 14, the pump shown in FIGS. 4 to 6 has a pair of plunger assemblies arranged transversely of the spindle to provide a symmetrical, double-acting pumping arrangement. In this particular construction, the pump body 10 is therefore provided with a pair of bores 19 each corresponding to the bore 18 of FIG. 2, and each containing a pump plunger assembly identical to the elements 22, 24 and 28 to 48 of FIG. 2. Upon the spindle 14 is mounted a symmetrically shaped cam 27, and the springs 28 urge the plungers 24 against the cam 27, so that on angular reciprocation of the spindle 14, as described with reference to FIGS. 1 to 3, the plunngers 24 are reciprocated in liners 22 to pump hydraulic medium from the reservoir 12 to the bores 19. A delivery conduit 51 is provided from each bore 19 to an outlet connection 52.

To provide for the exhaust of hydraulic medium back to the reservoir 12, this embodiment of the invention has a relief valve member 82 urged by means of a spring 84 against a seat 86 formed in a passage 88 extending through the body 10 from the outlet connection 52 to the reservoir. On the side of the valve seat remote from the outlet connection 52 (in the direction of exhausting hydraulic medium), the valve member 82 is continued as a plunger 90 which bears against a face cam 92 fixedly mounted on the spindle 14 adjacent the cam 27. Thus, by suitably setting the cam 92 on the spindle 14, the relief valve may be caused to open over a predetermined range of angular positions of the spindle.

Overload conditions between the pump and a hydraulic operating member which it supplies are avoided by the provision of an adjustable overload valve arranged in a passage 94 between the outlet connection 52 and the reservoir 12. The construction and operation of such overload valve are identical with that of FIG. 1, and therefore a detailed description need not be here repeated.

Both the embodiments of the invention described above are shown as having the pump body 10 provided with lugs 11 for securing to a vehicle chassis or comparable member, the lever arm 16 then being connected to some convenient part of the spring suspension system. The relative connections of said body and lever arm to the chassis or comparable member may, however, be reversed if desired.

A number of modifications are possible within the scope of the invention. For example, the pressure relief valve 56, 58 and 64 of FIGS. 1 to 3 may be be replaced by the relief valve 82, 86 and 99 of FIGS. 4 to 6. Again, although both embodiments of the invention are shown as having a single lever arm 16 adapted for connection to a vehicle or other suspension system, the spindle 14 may be arranged to extend from both sides of the body 10 in order to receive a wishbone suspension member instead of lever arm 16, i.e. the pump may be incorporated directly in said suspension system. Other practical applications of the pumps than to vehicle suspension systems are also possible, e.g. said pumps may be employed to supply hydraulic medium under pressure to vehicle hydraulically power'assisted steering and hydraulically 0perated clutch mechanisms, and in any other structure where a supply of hydraulic medium under pressure is required and means is available appropriately to reciprocate the spindle 14.

We claim:

1. A hydraulic pump comprising an at least partly hollow body member, the hollow interior of said body member constituting a reservoir for a hydraulic medium, a spindle journalled in and rockable relative to said body member and extending into the hollow interior thereof, said spindle being adapted for angular reciprocation from externally of said body member, said body member being formed with a pair of bores in parallel, side-by-side relation and each constituting a hydraulic cylinder, a reciprocable plunger received in each hydraulic cylinder and projecting from said cylinder into said hollow interior, a first cam carried by said spindle and extending symmetrically on either side thereof, spring means in each of said hydraulic cylinders for urging the plunger therein against said cam, whereby said cam is enabled to reciprocate said plungers responsive to turning movement of said spindle, each of said plungers being axially bored and counterbored, a valve seat in each plunger at the junction of the bore and counterbore therein, an inlet valve member resiliently urged against said valve seat for passing hydraulic medium from said reservoir through said plunger and into the hydraulic cylinder containing said plunger when said plunger moves in one direction in said cylinder, hydraulic medium outlet means in said body member, means including a pump delivery valve at the end of each hydraulic cylinder remote from the reservoir and connecting said remote ends of said cylinders to said outlet means for passing hydraulic medium from said cylinders to said outlet means when the plungers move in the opposite direction in said cylinders, said body member being formed with first and second passages extending between said outlet means and said reservoir, a plunger-operated hydraulic relief valve in one of said passages and having the operating plunger thereof projecting into said hollow interior, a second cam on said spindle and arranged to bear on said relief valve operating plunger for opening said relief valve whenever the spindle attains a predetermined angular position relative to said body member, and a pressure responsive overload valve in the other of said passages for permitting the flow of hydraulic medium from said outlet means to said reservoir whenever the pressure of hydraulic medium at said outlet means exceeds a predetermined value.

2. A hydraulic pump comprising an at least partly hollow body member, the hollow interior of said body member constituting a reservoir for hydraulic medium, a rockable spindle journalled in said body member and extending into the hollow interior thereof, said body member being formed with a pair of cylinders arranged in parallel, side-by-side relation and each opening at one of its ends directly into said hollow interior adjacent and in alignment with said spindle, a cam carried on said spindle within said hollow interior to register with one of said cylinder ends, a pump plunger displaceably received in the cylinder having its end registering with said cam, spring means in said cylinder urging one end of said pump plunger against said cam for reciprocating said plunger responsive to turning movements of said spindle, said plunger being axially bored and counterbored, a valve seat in said plunger at the junction of the bore and the counterbore therein, a pump inlet valve member resiliently urged against said valve seat for passing hydraulic medium from said reservoir through said plunger and into said pump cylinder when said pump plunger moves in one direction in said cylinder, hydraulic medium outlet means in said body member, means including a pump delivery valve connecting the other end of said pump cylinder to said outlet means for passing hydraulic medium from said pump cylinder to said outlet means when the plunger moves in the opposite direction in said cylinder, a plunger operated relief valve in the second cylinder and having the operating plunger thereof projecting into said hollow interior, passage means connecting the end of said second cylinder remote from said hollow interior with the outlet means and with the corresponding end of the pump cylinder, a second cam on said spindle and arranged to bear on the operating plunger of said relief valve for opening said relief valve whenever the spindle attains a predetermined angular position relative to said body member, a second passage extending between said reservoir and said first mentioned passage and joining said first mentioned passage at a position intermediate said first and second cylinders and apressure responsive overload valve in said second passage, for permitting hydraulic medium to flow from said outlet means to said reservoir whenever the pressure of hydraulic medium at said outlet means exceeds a predetermined value.

References Cited in the file of this patent UNITED STATES PATENTS =5,731 Ach July 29, 1902 1,706,309 Miller Mar. 19, 1929 1,982,770 Tollison 1- Dec. 4, 1934 2,044,814- Rothrock June 23, 1936 2,563,912 Belinkin Aug. 14, 1951 2,672,014 Yarger Mar. 16, 1954 2,687,311 Nallinger Aug. 24, 1954 2,784,978 Scale Mar. 12, 1957 2,825,579 Heiss Mar. 4, 1958 2,935,313 Momchildv et al. May 3, 1960 2,970,831 Wordsworth Feb. 7, 1961 2,970,832 Wordsworth Feb. 7, 1961 

1. A HYDRAULIC PUMP COMPRISING AN AT LEAST PARTLY HOLLOW BODY MEMBER, THE HOLLOW INTERIOR OF SAID BODY MEMBER CONSTITUTING A RESERVOIR FOR A HYDRAULIC MEDIUM, A SPINDLE JOURNALLED IN AND ROCKABLE RELATIVE TO SAID BODY MEMBER AND EXTENDING INTO THE HOLLOW INTERIOR THEREOF, SAID SPINDLE BEING ADAPTED FOR ANGULAR RECIPROCATION FROM EXTERNALLY OF SAID BODY MEMBER, SAID BODY MEMBER BEING FORMED WITH A PAIR OF BORES IN PARALLEL, SIDE-BY-SIDE RELATION AND EACH CONSTITUTING A HYDRAULIC CYLINDER, A RECIPROCABLE PLUNGER RECEIVED IN EACH HYDRAULIC CYLINDER AND PROJECTING FROM SAID CYLINDER INTO SAID HOLLOW INTERIOR, A FIRST CAM CARRIED BY SAID SPINDLE AND EXTENDING SYMMETRICALLY ON EITHER SIDE THEREOF, SPRING MEANS IN EACH OF SAID HYDRAULIC CYLINDERS FOR URGING THE PLUNGER THEREIN AGAINST SAID CAM, WHEREBY SAID CAM IS ENABLED TO RECIPROCATE SAID PLUNGERS RESPONSIVE TO TURNING MOVEMENT OF SAID SPINDLE, EACH OF SAID PLUNGERS BEING AXIALLY BORED AND COUNTERBORED, A VALVE SEAT IN EACH PLUNGER AT THE JUNCTION OF THE BORE AND COUNTERBORE THEREIN, AN INLET VALVE MEMBER RESILIENTLY URGED AGAINST SAID VALVE SEAT FOR PASSING HYDRAULIC MEDIUM FROM SAID RESERVOIR THROUGH SAID PLUNGER AND INTO THE HYDRAULIC CYLINDER CONTAINING SAID PLUNGER WHEN SAID PLUNGER MOVES IN ONE DIRECTION IN SAID CYLINDER, HYDRAULIC MEDIUM OUTLET MEANS IN SAID BODY MEMBER, MEANS INCLUDING A PUMP DELIVERY VALVE 